The case centred on a Glock 9mm and 338 rounds of ammunition that were found by police at the rented house Sgt Nightingale shared with another SAS soldier, known only as Soldier N, in 2011.

Police were acting on a tip-off from Soldier N's estranged wife who said there might be a gun stored at the home. The pistol was found in Sgt Nightingale's wardrobe and the ammunition was under his bed in a plastic box.

At the time, Sgt Nightingale told police that he had been given the pistol as a "trophy" at the end of a tour of duty in Iraq and had accumulated the ammunition in training exercises.

But he told the court martial that his confession had been false and that his memory was distorted by a brain injury he suffered during an endurance marathon in 2009.

He said he had "no recollection of receiving the gun" and that he was a "diligent" soldier who would not have "randomly" stored ammunition at home.